Seamless PDF Annotation Sync with PDF Expert 5’s Two-Way Sync

As a follow-up to my post on using Bookends, PDF Expert 5, and Dropbox to manage your PDF library, I thought I’d explain one of PDF Expert’s even more powerful features: two-way sync.

The primary benefit of two-way sync is that it is automatic. Instead of downloading files from Dropbox into PDF Expert, and then uploading them back to Dropbox when you’re finished reading and annotating them, PDF Expert will make sure that all of the documents in a selected folder are synced to and from the app as you make changes.1 In other words, if you annotate a file on your iPad in PDF Expert, the changes will automatically be synced to the file on Dropbox. Similarly if you make changes to a PDF file on your computer via Preview, for example, those changes will also be synced back to PDF Expert on the iPad, via Dropbox. “Two-way” is the keyword here.

Configuring Dropbox and Bookends for Mac

To begin, you’ll want to create a new folder in your Dropbox account that you’d like to two-way sync with PDF Expert. I simply chose to create a folder called “PDF Expert” within my Bookends » Attachments folder on my Dropbox. You could just as well name this folder anything and put it anywhere, but if you want to be able to add PDF reference attachments to the folder through Bookends, it must be placed within the default attachments folder for Bookends. Again, in my case, my default attachments folder is set to Dropbox » Bookends » Attachments, and thus I have added the “PDF Expert” folder within that directory.

Putting the two-way synced "PDF Expert" folder in my default Bookends "Attachments" folder will allow me to copy or move attachments directly to this folder via Bookends.

Putting the two-way synced “PDF Expert” folder in my default Bookends “Attachments” folder will allow me to copy or move attachments directly to this folder via Bookends.

Next, you’ll want to add some files to this folder. Remember that everything you put in this folder will be automatically synced to PDF Expert on your iPad. Among other things, this means that these files will take up local storage space on your iPad. From my experience, PDFs tend to add up quickly from a few megabytes to a few gigabytes, so be attentive to file size, or your iPad will soon be nagging you about its limited storage capacity.

One helpful point to bring up from my last post about Bookends, PDF Expert, and Dropbox is that with Bookends, you can choose where to store your reference attachments (i.e. PDFs) on a case by case basis. What I mean is that Bookends requires a default location for storing attachments, but it is possible to manually select a different storage location each time you add an attachment to a reference.

This is helpful for using two-way sync, as you can choose to copy or move a new attachment to the folder you are using for two-way sync if you want that attachment to sync automatically between PDF Expert and Dropbox.

All subfolders within your default Bookends attachments folder should populate in the drop-down menu next to “Folder.”

As you can see, when I go to attach a file to a reference in Bookends, I have the option to move or copy the file to the attachments folder. If you click the drop-down menu for the attachments folder, you should see any subfolders that exist within the default attachments folder for Bookends. In my case, I chose the “PDF Expert” subfolder since this is the folder I will be two-way syncing with PDF Expert on my iPad.

Once, I attach the PDF file to the reference in Bookends, it is moved or copied to the “PDF Expert” folder that I selected.

All of these files will automatically sync to PDF Expert once we set up two-way sync.

All of these files will automatically sync to PDF Expert once we set up two-way sync.

Syncing Files and Annotations with PDF Expert 5 on the iPad

Now that we have a folder to two-way sync with PDF Expert, along with some files in that folder, we’re going to move to the iPad to complete the two-way sync.

Open PDF Expert on your iPad, and tap your Dropbox account on the menu to the left (in my last PDF Expert tutorial, I explained how to connect your Dropbox account to PDF Expert). Find the folder you created that you wish to two-way sync with PDF Expert and tap it. It is important that you tap the folder to open it because when you tap the button to set up the two-way sync, PDF Expert will sync whichever folder you are currently in. Once you’re in the right folder, tap the word “Sync” in the upper right hand corner.

04-pdf-expert-two-way-sync

Here, I am in the “PDF Expert” folder on my Dropbox, so this is the folder that PDF Expert will set up two-way sync with when I tap “Sync.”

A popover will appear explaining a few details. Tap the green “Sync This Folder” button to continue.

If the sync successfully completes, you should see a brief popover confirming as much.

The two-way sync has successfully been set up.

The two-way sync has successfully been set up.

To test it out, let’s open up one of the files that synced from Dropbox, annotate it, and watch the two-way sync magic happen.

Adding a brand new annotation to test the two-way sync from PDF Expert to Dropbox.

Adding a brand new annotation to test the two-way sync from PDF Expert to Dropbox.

As you can see I’ve annotated another section of the Schiller text of which I am so fond. Once I’ve finished my annotations, I’ll return to the PDF Expert folder that I two-way synced.

PDF Expert identifies any file that has been recently edited or annotated and syncs the changes to Dropbox.

PDF Expert identifies any file that has been recently edited or annotated and syncs the changes to Dropbox.

If everything is working, you should see a small cloud icon at the top right corner of the document you just annotated. This means that the file is being automatically synced back to Dropbox. The cloud icon will disappear when the sync has completed, and back at your computer, you should receive a notification that a file on your Dropbox account has been updated. To double check, let’s open the Schiller text in Preview.

Open the same PDF in Preview, and voilà: the new annotations are there.

Open the same PDF in Preview, and voilà: the new annotations are there.

You can see that the annotations I made in PDF Expert on the iPad are there, exactly as they should be.

Completing the Two-Way Sync

It wouldn’t be fair, however, if we didn’t test the “two-wayness” of the “two-way” sync, so I’m going to add some annotations to the Schiller paper in Preview, save the file, and see if the changes appear in PDF Expert on the iPad.

Any annotations made in Preview (or most PDF reading and annotating applications) should sync just as well back to PDF Expert through Dropbox.

Any annotations made in Preview (or most PDF reading and annotating applications) should sync just as well back to PDF Expert through Dropbox.

When you return to the iPad and open PDF Expert, you should see two arrows forming a circle (the universal symbol for “sync,” I suppose) on the folder that we two-way synced earlier.

PDF Expert, via Dropbox, knows when a file has been altered and will sync the newest version of the file to the iPad's local storage.

PDF Expert, via Dropbox, knows when a file has been altered and will sync the newest version of the file to the iPad’s local storage.

This indicates that it is syncing the recently updated file from Dropbox to PDF Expert’s local storage. Once the arrows disappear, the folder should be synced up to date.

Note: if the sync doesn’t seem to be working, or if you just want to be sure, you can tap the folder, and once inside, you can swipe down in the file area to enact a manual sync (as you swipe down, you should see text at the top of the screen reading “Release to sync”).

Manually syncing your folders can help if PDF Expert doesn't seem to be recognizing a recently altered file (although I have never actually experienced this problem).

Manually syncing your folders can help if PDF Expert doesn’t seem to be recognizing a recently altered file (although I have never actually experienced this problem).

Sure enough, if we open the Schiller file in PDF Expert and turn to page 6, all of the annotations I made in Preview on my Mac are there. Pretty nifty.

The changes made in Preview show up just as they should in PDF Expert.

The changes made in Preview show up just as they should in PDF Expert.

I find this two-way sync especially useful because I use my iPad for reading material at home, and I use my MacBook in class for taking notes and having my annotated texts in front of me for discussion. If a new part of the text seems important during class, I can simply annotate the PDF with Preview, save it, and if I feel like reviewing the text when I get home, I can do so with the new annotations on my iPad, all thanks to PDF Expert and two-way sync. Again, you can do this through manual upload and download of files to and from Dropbox, but two-way sync makes this seamlessly automatic.

Keep in mind that anything you do with a file in PDF Expert will affect that file on Dropbox and, consequently, on other devices that are linked with your Dropbox. And vice versa, any changes that you make to files in the two-way synced folder on your Dropbox from another device (computer, smartphone, etc.) will affect the file in PDF Expert. This can be very useful, but it can also be very dangerous if you’re not careful (e.g. if you delete a file from a two-way synced folder on PDF Expert because your iPad is running low on storage, that file will also disappear from Dropbox and, consequently, from all other devices connected to Dropbox).

If you find yourself no longer wanting to two-way sync a folder, it’s easy to unsync that folder. Simply go to your Documents folder in PDF Expert, tap “Edit” at the top right of the screen, tap the folder that is currently two-way synced, and tap “Disable syncing.”

Note that you can also re-enable syncing if you tap the file once again in edit mode.

Note that you can also re-enable syncing if you tap the file once again in edit mode.

What’s nice about this is that any files in that folder will remain on your iPad’s local store in PDF Expert. This means you can make changes to the files, delete the files, or even delete the entire folder without having to worry about affecting the files on your Dropbox.

Not to be too bold, but this post combined with my last post on Bookends, PDF Expert, and Dropbox should give you all the information and tools you need to manage your PDF library as an academic (especially if you’re operating in an Apple ecosystem). Of course, there are always little nuanced tricks here and there, so as I think of or come across them myself, I’ll try to continually write new posts like these.

[1] It’s worth noting that other PDF annotation apps on the iPad are capable of two-way syncing as well. This article over at the very helpful Macademise blog discusses some of the benefits of GoodReader in comparison to other apps, including PDF Expert 5.

Leave a Reply